In modern times, people highly rely on portable electronic products such as cellular phones and tablet computers. In order that the portable electronic product can work for a long time, a rechargeable battery is additionally prepared. When the rechargeable battery is electrically coupled to the portable electronic product, the rechargeable battery charges the portable electronic product by using the electric power stored inside the rechargeable battery.
However, since the rechargeable battery has limited power capacity, the rechargeable battery needs a charger to maintain sufficient power after running out of battery power. Therefore, if losing the charger, the rechargeable battery cannot be charged. When going outside, it is troublesome and inconvenience since a user has to bring a charger additionally.
Accordingly, the inventor made various studies to solve the above-mentioned defects, on the basis of which the present invention is accomplished.